Feed-water precipitator



L. P. BARLQW FEED WAT ER PRECIPITATOR F lled June 28, 1924 awake: es fer P. 567F/0W Patented Dec. 21, 1926.

LESTER 1E. BARLOVI, 0F CLEVELAND, OHIO.

FEED-WATER PEEGIPIIATOR.

Application filed June 28, 1924. Serial No. 723,065.

My invention relates to a method and ap paratus for precipitating solidmattcr carried in solution by fresh water as itis supplied to a steam generating boiler and eliminating from the feed water so supplied the precipitated solid matter as well as any other solid matter.

It is well known that fresh water ordinarily contains more or less mineral, mainly in the form of bicarbonates of iron and the alkaline earth metals, in solution, and this mineral matter present in the water used for generating steam is precipitated in the boiler and forms deposits on the boiler plates in the form of boiler scale which lessens the efficiency of the boiler and may become highly dangerous. Many plans for preventing the formation of boiler scale and for. getting rid of scale have been devised. Various plans for purifying the feed water have been devised usually involving con siderable expense. invention to provide a method and apparatus by which at slight cost of apparatus and operation feed water may be so tr-eater. before it enters the boiler that the solid matter carried by it in solution will be precipitated and will be eliminated and the feed water will enter the boiler not only free from solid matter but also at substantially boiler temperature and pressur lVith the objects above indicated and other objects hereinafter explained in view, my invention consists in the method and apparatus hereinafter described and claimed.

Referring to the drawings:

Figure l is an outline side view of a steam locomotive showing a precipitator embodying my invention applied thereto;

Figure 2 is a cross sectional View on line 22 of Figure 1 on an enlarged scale;

Figure 3 is a partial side view of a modified form of the precipitator; and

Figure l is a similar side view of a further modification.

In the drawings, 1 indicates a steam generating boiler here shown as a locomotive boiler, and 2 indicates the box. 3 indicates the outer tube of the precipitator here shown as a horizontal tube arranged parallel with the longitudinal axis of the boiler and at a convenient height above the wheels. ld ithin and parallel with the outer tube 3 is an inner tube 4 having its axis above the axis of the outer tube and preferably with its upper periphery nearly in cont is the object of my tact with the upper'po'rtion of the interior of the outer tube so as to leave a considerable space indicated at 5between the lower portion of the periphery of the inner tube and the lower portion of the interior of the outer tube to form a chamber for precipitate.

Within the inner tube l and preferably fitting closely into its interior is a core l) having a relatively deep, helical groove 7 formed in it from end to end. In the lower portion of the inner tube a in line with the several convolutions of the helical groove are openings 8 preferably formed by cutting through the wall of the tube so as to form'tongues 9 and 10 of which tongue 9 is bent upward and inward and tongue 10 is bent downward and outward. u

The outer and inner tubes 3 and l are closed at their ends as shown. At the entrance end, the end nearest the fire box, an inlet pipe 11 extends through the upper portions of the tubes into communication with the entrance end of the helical groove 7, and at the discharge or forward end of the tubes, an outlet pipe 12 extends through the upper portions of the two tubes into con'in'uinication with the final convolution of. the helical groove. At the forward end of the outer tube 3, a discharge pipe 13 leads from the lower portion of the tube, that is, from the forward end of passage 5. This discharge pipe is provided with a controlling cook or valve 14: which is normally closed. i

Itwill be obvious that water forced o1- drawn into the inlet 11. will follow the helical groove after filling the space 5, and

will be discharged through outlet 12. The

stream of hot boiler water carrying with it the feed water, as it enters the end of the inner tube l tends to move in a straight line but is deflected by the core 6 outward against the inner face of the tube -l by which it is deflected inward and is caused to follow the helical path defined by the groove llll tend to move outward against the inner surface of tube 4. As these particles of solid material are brought opposite the openings 8 they will tend to drop through these openin by reason of their tendency to tangential movement. At each turn of the stream of water about the axis of the core 6, it will pass an opening 8 and solid precipitate or other solid material will, to a. greater or less extent, be caught by the tongue 9 and deflected outward into the chamber or space 5. Precipitated solid material thus caught in the chamber 5 may, at suitable intervals, be caused to be swept out of the chamber by opening cook or valve 14 and so permitting the water which enters through inlet 11 to temporarily pass through openings 8 and out through discharge opening 13.

The purpose of the precipitator is to col lect and thus eliminate from the feed water the mineral substances held in solution in and any solid mater carried by such water which, if not eliminated, will be deposited upon the interior of the boiler to form boiler scale, the harmful effect of which will be understood. It is known that a. temperature of 265 degrees F. or more will precipitate such mineral constituents as are ordinarily found in fresh water particularly if the feed water is quickly brought to this temperature. In order to bring the feed water to this temperature, it must be under high pressure since at atmospheric pressure water cannot be heated above 212 degrees F. By mixing with the feed Water a sufficient proportion of water at a temperature above 26.5 degrees, the temperature of the mixture of feed and boiler water may be brought to the temperature necessary to cause precipitation of the mineral constituents. To effect this, the heating avater must be at a temperature much above 265 degrees and, in order that it may be brought to and maintained at the required temperature, must be under pressure. In steam locomotives such as are used on railways, steam is ordinarily maintained at a pressure of 200 pounds or more, and at 200 pounds pressure, the temperature of the water is above 380 degrees F. By mixing with a relatively small quantity of cool feed water a relatively large quantity of water at 380 degrees or more, the feed) water may be quickly brought to the temperature, 265 degrees, necessary to cause satisfactory precipitation.

By my invention, the feed water sup-plied to a boiler at the usually slow rate of speed necessary to maintain the supply of water in the boiler as it is evaporated and used to drive the engine is mixed, before it enters the boiler, with a relatively large quantity of the water of the boiler at a temperature at or above 380 degrees and a pressure of "s not only by gravity but also 200 or more pounds per square inch, and it is essential to the operation of my invention that the boiler water be supplied to mix with the fed water by a positive forced feed. It is also important for practical purposes that the mixture of boiler water and feed water be permitted to deposit the precipitated material before it enters the boiler. The force by which the boiler water is supplied may be so applied as to drive the mixed waters through the precipitator or draw them through.

In the preferred form of the invention as shown in Figure 1, a pipe 20 leads from the boiler preferably at a point just above the top of the fire box where the heat is greatest to a pump 21, preferably a centrifugal or rotary pump operated by a steam turbine 22 such as is commonly used on locomotives for operating the generator for electric lighting. From the pump, a pipe 23 leads to the inlet 11 of the precipitator. Into this pipe 23 leads the fed water pipe 2 1 from the injector. 25, the fed water pipe being provided at any convenient point with a check valve 26. The outlet 12 of the precipitator is connected by pipe 27 having a check valve 28 arranged therein, with the boiler.

When the pump 21 is in operation, water is taken from the boiler at a temperature above 380 degrees and forced in relatively large quantity through (pipe 123 into and through the precipitator and is returned to the boiler through pipe 2?. Feed water at a relatively low temperature,- usually about 118 degrees, is supplied through feed water pipe 24- by the injector 25, or other usual means, to the pipe 23 in relatively small quantity and is at once mixed with the highly heated boiler water and is brought to a temperature above 2.65 degrees and its mineral constituents are precipitated in the form of fine particles. As the mixed waters pass through the convolutions of the spiral groove 7 and are swept past the successive openings 8, the fine particles of solid material are caught by the tongues 9 and deflected downward into chamber 5. The feed water thus freed from impurities passes with the boiler water into the boiler through pipe 27.

When the precipitated material accumulates in the chamber 5, the cock or valve 14 may be opened to permit boiler water under pressure to pass through the openings 8 to stir up the solid matter and drive it out through pipe 13.

Instead of having the feed water pipe lead to the pipe 23, that is between the pump and the precipitator, it may lead to the pipe 20 as shown in Figure 3 so as to permit the feed water to be drawn into the pump with the boiler water.

Also, if preferred, the pump may be arranged in the pipe 27 at the outlet end of the precipitator as shown in Figure 4;, it being essential only that the boiler water be forced into or drawn into the mixing chamber and the precipitator in such quantity relative to the feed water as to quickly heat the feed water to the temperature required for precipitation.

Having thus described my invention, what I claim is:

1. The method of precipitating mineral matter held in solution in feed water and separating the precipitate from the water which consists in maintaining a rapidly flowing stream of hot water of relatively large volume'from one portion of the boiler to another portion thereof, supplying relatively cool feed water in relatively small vol ume and mixing the same with said steam to cause mineral matter carried in solution in said feed water to be precipitated by the heat of the hot boiler water, and separating the precipitate from the water of the flowing stream by causing the flowing stream to follow a helical path about a horizontal axis at such speed as to cause the precipitate to be carried to the outside of the helical path by the momentum due to its specific gravity being greater than that of the water.

2. The method of precipitating mineral matter held in solution in feed water and separating the precipitate from the water which consists in maintaining a rapidly flowing stream of hot water of relatively large volume from one portion of the boiler to another portion thereof, supplying relatively cool feed water in relatively small volume and mixing the same with the stream to cause mineral matter carried in solution in said feed water to be precipitated by the heat of the hot boiler water, separating the precipitate from the water of the flowing stream by causing said flowing stream to follow a helical path about a horizontal axis at such speed as to cause the precipitate to be carried to the outside of the helical path by the momentum due to its specific gravity being greater than that of the water, and permitting the separated precipitates to fall into a body of relatively still water.

3. In an apparatus toreliminating solid matter from feed water, a precipitate eliminator comprising an inner tube having at one end an inlet and an outlet at the other end and a cylindrical core fitting within the tube with its outer surface in contact with the inner surface of the tube and having a helical groove in its outer surface extendingfrom end to end thereof in communication with the inlet and outlet of the tube to form with the inner surface of the tube a helical passage and means for forcing water through said helical passage, an outer tube of greater diameter thanthe inner tube surrounding said inner tube and an opening in the inner tube communicating with the passage and with the outer tube for escape of precipitates from the inner tube into the outer tube.

In testimony whereof I afiix my signature.

LESTER P. BARLOl/V. 

